degree of degradation
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2022 ◽  
Vol 12 (1) ◽  
pp. 459
Author(s):  
Ioan Bitir ◽  
Rudolf Derczeni ◽  
Aurel Lunguleasa ◽  
Cosmin Spirchez ◽  
Valentina Ciobanu

Forest roads are of great economic importance as they ensure the transport of logs and forest biomass toward collection and processing centers, which is why they should be evaluated periodically, in order to establish the degree of degradation and periodicity and rehabilitation methodology and procedures. The main purpose of the paper is to follow the behavior of the Ciobanus forest road through specific tests over a difficult season of 5 months, in order to diagnose the degree of surface wear and structure degradation. Regarding the traffic on this forest road, an exhaustive study was made during the 2013–2017 period, and for in situ or in laboratory tests a more complex study during the year 2018, in the March-June period was also made. Out of the total of 20 tests that evaluated the Ciobanus forest road, 5 of them were classified as appropriate and 15 unsuitable for traffic, meaning the forest road had to be completely rehabilitated. Moreover, it has been shown that this forest road is part of the category of secondary forest roads and needs a total overhaul to cope with the increasing traffic or tonnage of trucks. Through the methodology and the obtained results, the paper supports the specialists in the field of forest roads to be able to diagnose or evaluate such a road, and to realize a program and its timing for maintenance.


Author(s):  
Mohamed Kayid ◽  
Lolwa Alshagrawi

Although the ordinary time-to-failure degradation-based model has been extensively used in practice, it also has its limitations. In this paper, we consider a time-to-failure degradation-based model recently proposed by Albabtain et al., where a limiting conditional survival probability entertains further stochastic relationships between the failure time and the degree of degradation. In the particular case where the limited survival probability is available for the proportional failure rate model, the model is developed using two well-known degradation paths, namely the additive degradation path and the multiplicative degradation path, each of which has a component of random variation. Preservation of various stochastic orders and aging properties of the random variation component in the model in the described setting is developed. To illustrate the model in the modified design, some examples of interest in reliability are presented.


2021 ◽  
Vol 105 (1) ◽  
pp. 431-440
Author(s):  
Pavel Šafl ◽  
Jana Zimáková ◽  
Tomáš Binar

The aim of this work is to study the climatic influences on 3D printed materials. This study focuses on the HIPS material, which was chosen as the starting material for further studies. The material in the field of 3D printing is known for its rapid photooxidation, which results in the formation of cracks in the final product. A climatic chamber was used for degradation, in which UV light, heat and increased humidity were applied to the material. The degree of degradation was then checked by tensile test and electron microscope.


2021 ◽  
Vol 25 (11) ◽  
pp. 30-35
Author(s):  
O.A. Pasko ◽  
A.V. Zakharchenko

The assessment of the degree of degradation of the soil and vegetation cover in the territory of storage of snow masses was carried out. It is established that in the soils of the polygons there is a decrease in the reserves of organic carbon, an increase in the power of the abiotic alluvial layer, a reduction in the power of the upper part of the soil profile, washouts and algae are formed. It is determined that the soil filtration coefficients are low. Stagnation of water near the surface and prolonged waterlogging against the background of low temperatures during the entire period of snowmelt were revealed. The soils of all snow polygons are characterized as highly degraded. They have lost their valuable functions for humans and need to be reclaimed.


Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3840
Author(s):  
Monika Chomiak ◽  
Maciej Rojek ◽  
Józef Stabik ◽  
Małgorzata Szymiczek

The operating conditions of thermoplastic polymer materials determine the changes in their functional properties. Accelerated aging tests do not give a full picture of the changes taking place in the polymer material, hence the conclusions drawn on the basis of exposure of these materials to damaging effects in real operating conditions are particularly important. The aim of the study was to determine the degree of degradation of polypropylene films used in the drainage blocks of cooling towers in a selected power plant in the Silesian voivodship, which allowed forecasting the operating time over a period of 10 years. A number of 600 mm high drip blocks were tested, on which 300 mm high blocks were mounted. The tests were carried out on films subjected to the aging process in the conditions of continuous operation of a cooling tower (almost 100% humidity). The water flow is accompanied by heat exchange, the side effect of which is deposits formation on the surface of the drip blocks, negatively affecting the operation of the cooling tower. The degree of degradation resulting from operational aging was assessed on the basis of the strength properties determined in the static tensile test, thermogravimetric analysis and FTIR spectra. Changes in properties during operation were determined on the basis of the obtained results of the strength tests, which were compared with the tensile strength and elongation at break of reference samples (not subjected to aging in the operating conditions of cooling tower drip blocks). The obtained results were related to the properties of the reference samples not subjected to the degradation process. Based on the collected data, the tensile strength and deformation at fracture after a 10-year service life were predicted.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Darko Lovrec ◽  
Vito Tič

Purpose Apart from the basic material properties of liquid lubricants, such as, e.g., the viscosity and density of the hydraulic fluid, it is also important to have information regarding the electrical properties of the fluid used. The latter is closely related to the purpose, type, structure, and conditions of use of a hydraulic system, especially the powertrain design and fluid condition monitoring. The insulating capacity of the hydraulic fluid is important in cases where the electric motor of the pump is immersed in the fluid. In other cases, on the basis of changing the electrical conductive properties of the hydraulic fluid, we can refer its condition, and, on this basis, the degree of degradation. Design/methodology/approach The paper first highlights the importance of knowing the electrical properties of hydraulic fluids and then aims to compare these properties, such as the breakdown voltage of commonly used hydraulic mineral oils and newer ionic fluids suitable for use as hydraulic fluids. Findings Knowledge of this property is crucial for the design approach of modern hydraulic compact power packs. In the following, the emphasis is on the more advanced use of known electrical quantities, such as electrical conductivity and the dielectric constant of a liquid. Originality/value Based on the changes in these quantities, we have the possibility of real-time monitoring the hydraulic fluid condition, on the basis of which we judge the degree of fluid degradation and its suitability for further use.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
J. May-Crespo ◽  
P. Martínez-Torres ◽  
P. Quintana ◽  
J. J. Alvarado-Gil ◽  
L. Vilca-Quispe ◽  
...  

Color-induced changes in stones due to heating can be useful in determining the degree of degradation generated in their components and structure. We evaluate the effect of heating in three types of limestones, useful in building and restoration, corresponding to biomicrite (BC), biosparite (BS), and intramicrite (IM), in the range of temperature from 100°C to 600°C. Our analyses indicate that the strongest changes in reflectance occur in the samples of intramicrite, followed by biomicrite, being biosparite showing the smallest ones. Additionally, IM samples suffer the largest modifications in effective porosity due to the thermal treatment; in contrast, BS and BC samples show smaller temperature-induced alterations associated with smaller changes in reflectance. Moreover, we reveal that most of the thermally induced variations are associated, in this range of temperature, to the dehydroxylation of goethite that transforms into hematite, as well as by the burning and partial release of the organic matter present in the rock. Colorimetry analyses show that the sequence of thermally induced changes can be followed by the evolution of the three coordinates, L ∗ (lightness), a ∗ (red-green), and b ∗ (yellow-blue), of the CIE 1976 L ∗ a ∗ b ∗ space.


Author(s):  
P. Bulakh ◽  
Volodymyr Shvets ◽  
О. Maslo

In the express diagnostics of the condition of the material of the elements of the structures in operation and the materials for the manufacture of the responsible elements of the equipment, it is necessary to take into account the current damage. At the same time, non-destructive methods of control are more relevant, which allow to assess the level of scattered damage in the material and the degree of degradation of its structure of the metal. Another important factor in controlling the current state of the material is the assessment of the residual life of the structural element under operating loads. This paper presents the results of research on the application of the non-destructive method of LM-hardness in assessing the characteristics of the limiting state of the material of real structural elements operating under low-cycle load.


2021 ◽  
pp. 56-65
Author(s):  
Irina Olegovna Reshetnikova ◽  
Sergey Vasilievich Metlitskikh ◽  
Nadezhda Dmitrievna Stekleneva ◽  
Aleksandr Nikolaevich Volov

A high-resolution HPLC–MS/MS method was proposed for the study of solutions of standards of specific impurity B contained in the substance of the drug «Lomustine», which is included in the List of Vital Medicines. A characteristic degradation product of specific impurity B, the content and quantity of which is not regulated by the European Pharmacopoeia, has been found.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5150
Author(s):  
Magdalena Broda ◽  
Morwenna J. Spear ◽  
Simon F. Curling ◽  
Graham A. Ormondroyd

Waterlogged wood treatment with methyltrimethoxysilane (MTMS) proved effective in stabilising wood dimensions upon drying (anti-shrink efficiency of 76–93%). Before the method can be proposed as a reliable conservation treatment, further research is required that includes the evaluation of the mechanical properties of treated wood. The aim of the study was to characterise the effect of the treatment on the viscoelastic behaviour of archaeological waterlogged elm and oak wood differing in the degree of degradation. Dynamic mechanical analysis in the temperature range from −150 to +150 °C was used for the study. To better understand the viscoelastic behaviour of the treated wood, pore structure and moisture properties were also investigated using Scanning Electron Microscopy, nitrogen sorption, and Dynamic Vapour Sorption. The results clearly show that methyltrimethoxysilane not only prevents collapse and distortions of the degraded cell walls and decreases wood hygroscopicity (by more than half for highly degraded wood), but also reinforces the mechanical strength by increasing stiffness and resistance to deformation for heavily degraded wood (with an increase in storage modulus). However, the MTMS also has a plasticising effect on treated wood, as observed in the increased value of loss modulus and introduction of a new tan δ peak). On the one hand, methyltrimethoxysilane reduces wood hygroscopicity that reflects in lower wood moisture content, thus limiting the plasticising effect of water on wood polymers, but on the other hand, as a polymer itself, it contributes to the viscous behaviour of the treated wood. Interestingly, the effect of silane differs with both the wood species and the degree of wood degradation.


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